Oil burning apparatus



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s. CHADWICK ET AL 2 0 27 632 OIL BURNING APPARATUS Original Filed July 27, 1929 5 She ets-Sheet 1 jam, M, 1936.

L. S. CHADWICK ET AL OI L BURNING APPARATUS s Sheets-Sheet 2 Original Filed July 27, 1929 Jam, 114 1%36 5 (jHADWEQK E AL 2,27,32

OIL BURNING APPARATUS Original Filed July 27, 1929 3 Sheets-Sheet 5 Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE OIL BURNING APPARATUS poration of Ohio Original application July 27, 1929, Serial No. 381,600. Divided and this application April 1, 1938, Serial No. 663,962

2 Claims.

This invention relates to rotary oil burners of the kind intended especially for use in domestic furnaces, and it has to do more particularly with the hearth of such burners, this application being a division of one, directed to the burner structure, generally, filed by us on July 27, 1929, and bearing Serial No. 381,600, now Patent No. 1,911,264, dated May 30, 1933.

The purpose of the invention which constitutes the subject matter hereof is to provide a hearth that, by reason of its nature and relation to the fuel atomizer, greatly enhances combustion, rendering the same practically complete; contributes to the production of a steady and highly satisfactory flame that, by reason of its character, may be easily and accurately controlled; and renders ignition of the burner from the pilot light or igniter more certain and rapid.

In the following detailed description of the invention reference is made to the accompanying drawings wherein Fig. l is a central vertical section from front to rear through our improved oil burning apparatus and the adjacent parts of the furnace in which it is installed, the oil reservoir and atomizing cup, with the latters associated parts being shown in elevation; Fig. 2 is a similar section through the upper portion of the apparatus on a scale considerably enlarged over that of Fig. 1, and showing the oil reservoir, atomizing cup, and parts associated therewith, in section; and Fig. 3 is a horizontal section, on the line 3-3 of Fig. 1, parts of the atomizing cup and hearth being broken away.

The furnace, the lower portion of which is shown in Fig. 1, is designated A, and the same is of standard type and construction, and access is had to the ashpit d thereof through the usual opening a. The bottom of the ashpit is shown as formed by the floor a and above the ashpit is the firebox or combustion chamber designated a Our improved burner consists of three major parts which may be referred to, generally, as the lower or bottom unit assembly I, the upper or top unit assembly 2, and the hearth 3. The structure comprising these major parts is supported a suitable distance above the floor a by legs 5, preferably three in number, with the hearth 3 disposed in the lower portion of the fire box or combustion chamber a The lower unit assembly I is made up of a circular bottom Wall 6, a cylindrical wall I, and an annular top wall 3, all suitably connected together, as by spot welding or otherwise.

The inner end of an air supply duct I5, shown in Fig. 1 as formed of telescoping sleeves, is fitted through an opening in the front portion of the cylindrical wall I of the bottom unit assembly I, the forward end of said duct projecting through a plate I! which closes the ashpit opening a of the furnace.

An electric motor 30 is suspended, through bolts 3|, from the annular top wall 8 of the lower unit assembly I, the casing. of the motor having a circular extension 32 that fits within the opening of said annular wall. The motor shaft 33 extends a material distance above the wall 8 and has in its end a transverse notch 35, the upper portions of whose side walls are flared outwardly, as shown at 36.

The top unit assembly 2 includes a pan-like housing whose body portion is drawn from sheet metal to form a bottom 40 and a side wall 4|. The upper edge of said wall is flanged outwardly at 42, and suitably secured thereto is the periphery of a top 43, the central portion of which is offset upwardly to form a cylindrical extension 44. Said extension has formed integral with it an annular wall 45 that surrounds an opening 46.

The hearth proper is made of suitable refractory material, such as fire clay or brick, preferably in segmental sections, as shown, and the same includes a rim 48 that rises from the edge of a fiat bottom wall 49, and this refractory body is contained within a sheet metal hearth receptacle that is supported by the top wall 43 of the upper unit assembly 2. The hearth receptacle is shown as secured to the top wall 43 by screws 5| Whose heads are accommodated by a cavity in the bottom wall 49 of the hearth. Situated centrally, and secured to the bottom 40, of the aforesaid housing that constitutes a part of the upper unit assembly, is a reservoir 55, to which fuel is conducted by a supply pipe 56. It may be explained that by suitable means (not shown) such as a float control, or an overfiow device, the oil is maintained at about the level indicated by the line it in Fig. 2. It will be noted that the bottom of the reservoir is formed with a re-entrant portion 51 (Fig. 2) that rises to almost the height of the peripheral wall. A baffie 59 rises from the bottom of the reservoir in concentric and spaced relation to the re-entrant portion 51 and the same has a series of ,holes 58 adjacent its lower end through which the oil spaces inwardly and outwardly of the baffie communicate.

Dipping into the reservoir below the normal oil level therein and inside the baffle 59 is the receiving end 68 of an atomizing cup 6| that is supported through a disk-like member 62 from a head 63 that includes an elongated hollow hub 64 that fits over the motor shaft 33, a pin 65, that extends transversely through the hub, occupying the notch 35 in the motor shaft. By this means a driving connection is effected between the atomizing cup and motor shaft. The supporting member 62 is provided with a series of openings 66 that overhang the shoulder 61 that is formed between the enlarged upper end of the atomizing cup and the receiving end 60 thereof. The receiving end and bowl of the cup are upwardly divergent and the latter is flared outwardly at its upper or discharge end to provide a lip 68. An annular member 69 surrounds the receiving end of the cup a short distance above the baiile 59 and serves to arrest upward flow of oil about the exterior of said end of the cup and return it to the reservoir, thus preventing its escape into the housing of the top unit assembly.

To protect the interior of the atomizing cup from the intense heat of the products of combustion in the fire box a of the furnace, a socalled cooling bell l occupies the cup, and said bell has a cover H which extends a material distance beyond the periphery of the bell and is of considerably greater diameter than the atomizing cup. A ring 12 is spaced below the overhanging portion of the cover ll and is connected thereto by fastening means l3, a space 14 being thus provided between sand ring 12 and the edge portion of the cover H. The bottom of the bell 18 is spaced from the supporting member 62 by thimbles, one of which is shown at 15 in Fig. 2, and said thimbles have threaded bores for the reception of screws 16 that secure the bell and the supporting member 62 to the head 63. Rivets l1 connect the edge portion of the supporting member 62-, the shoulder 6'! of the atomizing cup, and a ring 18 together, said ring, in turn, having secured to its peripheral portion, as by rivets 19, a shell 80 which extends upwardly about the atomizing cup, and immediately below the lip 68 thereof is equipped with radial fan blades 8|.

The bottom and top unit assemblies l and 2 are secured together by screws 85 and the portions of their respective walls 8 and 40 that are in engagement with each other are provided with large registering openings, those appearing in Fig. 2 being indicated at 86. The wall 8 has smaller openings 8'! immediately adjacent the motor casing, and through these smaller openings the interior of the bottom unit assembly communicates with a space 88 provided by the elevated central portion of the wall 40. It will be noted from Fig. 2 that the central opening of said wall 48 is approximately of the same diameter as the re-entrant portion 51 of the reservoir 55, and that the top of said re-entrant portion is open to the interior of the receiving end 60 of the atomizing cup. The purpose of this. will later appear.

A pilot burner 98, preferably a gas burner, is located within the lower front portion of the hearth 3, and the same is connected to a gas supply line 9| that includes a mixer 92 through which primary air is admitted to the burner.

Current is supplied to the motor 3!] through suitable conductors (not shown) and when said motor is energized, it whirls the atomizing cup at a relatively high rate of speed, the direction of rotation being from left to right as the parts are viewed in Fig. 1. By reason of the gradual upward divergence of the receiving end and bowl of the cup, oil, through centrifugal action, is caused to travel up the receiving end of the cup, through the openings 66, and upwardly across the inner surface of the cups bowl in a thin film to the discharge end or lip 68 from which it is hurled outwardly in a spray or sheet over the bottom wall 49 of the hearth toward the rim 48 thereof. At the same time, due to the action of the fan blades 8|, air is drawn in through the supply conduit l upwardly through the interior of the bottom unit assembly about the motor 30, through the holes 81, space 88, the interior of the re-entrant portion 51 of the oil reservoir and through the same openings 66 of the supporting member through which the oil rises into the bowl, and the major portion of this air that rises through the cup is hurled outwardly and intermixed with the oil, while the remaining part passes out through the space 14 between the ring 12 and the overhanging edge portion of the cover H to prevent overheating of the same. Additional air is drawn upwardly through the relatively large openings 86 and through the housing of the top unit assembly and out by way of the central opening 46 in the upwardly extended portion in the top wall 43. In other words, the fan comprising the blades 8| acts toinduce a draft of air upwardly through the oil reservoir, the interior of the cup and the space 14 of the cooling bell and a second draft of air upwardly about the exterior of the reservoir and atomizing cup. This entraining of the air about the burner parts has two advantages: first, that of maintaining the burner parts relatively cool; and, secondly, that of preheating the air so that it will have a vaporizing effect upon the fuel oil. Thus, in our improved burner, the oil is not only atomized by mechanical means, but vaporized by a thermal action. Immediately after the motor is started and the oil and air are hurled outwardly into the confines of the hearth, the combustible mixture is ignited by the pilot burner 98 and is deflected upwardly by the rim of the hearth.

By forming the rim of the hearth with the groove I08 in the plane of the discharge end or lip 68 of the atomizing cup, so that the mixture of oil and air is hurled into said groove, a turbulence is set up that greatly enhances combustion, rendering it practically complete. Furthermore, the groove I00 arrests oil that would otherwise be washed up the rim of the hearth by the underneath blast of air, thus retaining the flame steady and preventing it from fluctuating to any material extent. In other words, the base of the major portion of the flame-that adjacent the rim of the hearth-is prevented from being blown away, so to speak, and this condition, besides promoting a highly satisfactory fire, enables the fire to be more easily and accurately controlled. A further and important virtue of the groove is that, in holding the oil, it causes ignition from the pilot burner or igniter to take place with greater rapidity and certainty, i. e. the flame is quicker and more positive in encircling the entire hearth.

Having thus described our invention, what we claim is:

1. In a rotary oil burner, the combination of an atomizing cup supported for rotation on a substantially vertical axis and whose lip constitutes its discharge end, means for supplying oil to said cup, means for spinning the cup, and a hearth rim surrounding the cup in spaced relation thereto, said hearth rim flaring upwardly at a slight angle to the vertical and having an inwardly facing circumferential groove, having its center in substantially the plane of the discharge end of the cup, the inner surface of the rim above and immediately below the groove being in a substantially common plane.

2. In a rotary oil burner, the combination of an atomizing cup supported f or rotation on a substantially vertical axis and whose lip constitutes its discharge end, means for supplying oil to said cup, means for spinning the cup, and a hearth surrounding the cup beneath the horizontal plane of its discharge end and having a rim rising above said plane, said rim having an inwardly facing circumferential groove having its center substantially in said plane, the inner surface of the rim above and immediately below said groove being in a substantially common plane and merging with the top surface of the hearth inwardly of the rim.

LEE S. CHADWICK.

MARC RESEK.

JOHN ALGER DAHLSTROM. 

